Erosion wear of HCCI alloys

Abstract

Failures in industrial plants, which operate under extreme conditions, could occur after a short time of exploitation. Erosion wear of materials is caused by the relative movement of solid particles and the surfaces of components. Such erosive wear can lead to the failure of industrial components in a very short time and/or a sharp decline in the structural integrity of industrial equipment. For example, the wear of the ash disposal system in a coal-burning thermal power plant, due to impact of ash particles with a high content of mineral residues, is a very common case of failure and outages in the operation of such industrial systems. Two high chromium cast irons (HCCI) were tested to determine the erosion wear. These alloys contain 15% Cr and 25% Cr, and it was tested in as-cast and after heat treatment (annealing). A specially designed installation was used for the gas blast sand erosion test. Type of erodent was foundry quartz sand. Erosion tests were done with high erodent particle velocity (90 m/s) and high erodent feed rate (3000 g/min). This conditions represents those similar to extreme wear conditions of some components of thermal power plants using pulverized high mineral content coals. Microstructural characterization was done at samples before and after erosion tests, Fig. 1. The main results indicate that matrix plastic deformation and distribution of carbide phase have a significant contribution to erosion resistance of HCCI alloys in such conditions.